The Jackson Laboratory (TJL) Cancer Center has 48 members organized into a single program, Gene Discovery and Analysis, Research focuses on genetic approaches for analyzing individual steps in the progression to cancer. In advancing this strategy, TJL researchers develop new tools for genetic analysis, which are used here and disseminated to the wider scientific community for work on the molecular and cellular bases of cancer. Virtually all TJL Cancer Center research uses genetically defined mice as the premier mammalian model for identifying and analyzing the genes that regulate these processes. Resources provided by the Cancer Center are the foundation of this research, supporting genome-scale gene discovery via QTL analysis, mutagenesis and positional cloning and functional analysis via gene targeting, transgenesis, phenotypic analyses, and expression arrays. The scientific leadership of TJL has direct oversight of the Cancer Center. Dr. Kenneth Paigen is the Director of TJL and the Cancer Center. Dr. Barbara Knowles, Associate Director of TJL and the Cancer Center, is also Director for Research at TJL and Program Leader at the Cancer Center. Support is requested for Scientific Resources and Services. Resources include the Mouse Models Resource, which provides spontaneous and induced mutant mice to Cancer Center staff, Cryopreservation and Rederivation Resource, for economical maintenance of strains at high health status, Veterinary Medicine Resource for ensuring animal health, the Diagnostic Laboratory Resource for consultation in clinical and anatomical pathology, and the Computational Biology Resource, which provides staff with access to expertise and analytical tools for advanced computational and statistical analysis. Scientific Services include Biological Imaging for complete histological analyses, Cell Biology and Microinjection for transgenic and targeted mutagenesis services, Flow Cytometry for a full suite of sorted and analysis services, and Microchemistry for molecular biological resources. Funds are requested for development of new techniques in these resources and services through a pilot program. Support is also requested for new investigators who will bring additional strength to the TJL Cancer Center's focus on mouse genomic and biological approaches to gene discovery in cancer research.